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Diatomaceous Earth

Diatomaceous earth, or diatomite, is a soft sedimentary rock that is easily crumbled into a near-white powder. It consists of diatoms, the fossilized remains of a special group of ocean-floating single-celled organisms, commonly known as phytoplankton. As a powder, diatomaceous earth can be used as an insecticide. The fine powder absorbs lipids from the waxy outer layer of insects' exoskeletons, causing them to dehydrate. Because of the drying and absorbing power of the powder, diatomaceous earth can also be used on the ground around plants to discourage snails, slugs and crawling insects. Diatomaceous earth can also be used indoors to control cockroaches, ants, silverfish, crickets. millipedes, centipedes, fleas, carpet beetles and bedbugs.

Natural diatomaceous earth is virtually nontoxic to man and other mammals, but it can cause extreme nasal irritation if inhaled. The kind of diatomaceous earth used as a filtering agent in swimming pools, however, has been heat treated and contains crystalline silica. It is a definite respiratory hazard, leading to possible silicosis, and should not be used in the garden. Read and follow all label directions and safety procedures.

Missouri Botanical Garden, 2001-2011